This epidemiological study would investigate the risk of mortality among two groups of bereaved parents: a) those who lost a son in war and b) those who lost an adult son in an accident. In addition, it explores the role of some of the socio-demographic factors associated with the risk of mortality; the effects on this risk of the social support system and of the new social role which have evolved from governmentally established procedures to assist the war-bereaved parents; and, finally, it evaluates the effect on the risk of the support provided by a naturally available, well developed social system (the Kibbutz), for both groups of parents. This study will be conducted in Israel, a country which has recently suffered several wars and where there are excellent facilities for epidemiological research, such as population and death certificate registers. The governmentally established procedures and the contrasting social organizations (Kibbutzim/cities) existing in Israel offer unique opportunities for studying the effects of broadly-based support systems on the reactions to bereavement. The registers will be used to identify the two groups of bereaved parents and their respective mortality rates will be compared with that of the general population controlling for relevant socio-demographic factors. An analagous procedure will be used for the comparison of the mortality rates of Kibbutz/non-Kibbutz parents. This study, which explores a subject almost completely neglected in bereavement research, capitalizes on an "experiment of nature" thus contributing to the understanding of theoretical issues related to health and illness. It will also provide information for the planning of appropriate health intervention measures.